This invention relates to signal interface circuits and more particularly to a signal interface circuit for receiving synchronizing signals for a television monitor.
Electronic devices such as video games and home computers which are interfaced with a separate television monitor for visual display purposes, can be arranged to generate line and field synchronizing signals for the television monitor separately from video or RGB signals.
However, some forms of these electronic devices may provide synchronizing signals comprising positive going pulses, while others may provide synchronizing signals comprising negative going pulses. In order to cater for these possible alternative pulses, it is known for a separate television monitor to incorporate manual switching means for selecting the particular synchronizing pulse sense or polarity that the television monitor is to respond to, as determined by an electronic device with which it is interfaced.